In compression/decompression (codec) systems, compression efficiency and video quality are important performance criteria. For example, visual quality is an important aspect of the user experience in many video applications and compression efficiency impacts the amount of memory storage needed to store video files and/or the amount of bandwidth needed to transmit and/or stream video content. For example, a video encoder compresses video information so that more information can be sent over a given bandwidth or stored in a given memory space or the like. The compressed signal or data may then be decoded via a decoder that decodes or decompresses the signal or data for display to a user. In most implementations, higher visual quality with greater compression is desirable.
In some approaches, such as the High Efficiency Video Coding (HEVC) standard, sample adaptive offset (SAO) techniques may be used. For example, SAO filtering may be performed after deblock filtering to provide better picture reconstruction by applying offsets. SAO filtering may, for example, improve picture quality, reduce banding artifacts, and reduce ringing artifacts. In some contexts, the complexity of SAO coding is relatively small compared to other coding modules. However, in some contexts, SAO coding may become the bottleneck of the coding pipeline. Moreover, although the amount of additional bits used by SAO is a relatively small percentage of the overall bitstream and usually will not affect rate control under moderate to high bitrate applications, it may cause problem in low bitrate coding
It may be advantageous to perform effective and efficient compression of video data in all contexts including those that may be negatively impacted by SAO coding. It is with respect to these and other considerations that the present improvements have been needed. Such improvements may become critical as the desire to compress video data becomes more widespread.